The present invention generally relates to power hand tools and more particularly to a switch assembly of the type used with power hand tools to prevent contamination of power hand tool switch assembly components.
There has been continued innovation and improvement in the design of power hand tools of the type that are used in cutting drywall. Examples of such products are those sold under the Bosch brand produced by the Robert Bosch Tool Corporation. These power hand tools have a generally cylindrically shaped housing to which a removable handle can be attached, with the housing containing a drive motor having a rotary output shaft to which a side cutting bit can be attached. When cutting drywall, there is usually a significant amount of dust that is produced and tends to coat the unit. To selectively control the motor, such power hand tools are further provided with an electrical switch assembly that typically has multiple operating positions for operating the tool at different speeds.
While such switch assemblies in the form of slide-type switch operation have been available for many years, a recurring and persistent problem has been dust contamination of the switch assembly components, which can eventually result in switch assembly failure. While it is possible to purchase elaborately constructed switch assemblies that are tightly sealed so that dust cannot enter the switch components of the assembly, such sophisticated switch assemblies are significantly more expensive than the slide-type switches that are currently in commercial use.